A virtual machine (VM) is a software implementation of a machine that executes programs like a physical machine. Virtualization software allows multiple VMs with separate operating systems to run in isolation on the same physical server. Each VM may have its own set of virtual hardware (e.g., RAM, CPU, NIC, etc.) upon which an operating system and applications are loaded. The operating system may see a consistent, normalized set of hardware regardless of the actual physical hardware components. A virtual center may operate to control virtual machines in data centers and, for example, in connection with cloud computing. The virtual center may further include a virtual data center that provides logical control and management of data storage in a data center, and provides for sub-dividing contents of virtual components into compute resources, network resources and storage resources.
Configuring and deploying VMs is known in the field of computer science. For example, U.S. Pat. No. 7,577,722 to Khandekar, et al., entitled “Provisioning of Computer Systems Using Virtual Machines,” which is incorporated herein by reference, discloses techniques for configuring and deploying a VM according to user specifications. VMs may be provisioned with respect to any appropriate resource, including, for example, storage resources, CPU processing resources and/or memory. Operations of VMs may include using virtual machine images. A VM that may be moved between different locations and processing thereafter continued without interruption. Reference is made to U.S. Pat. No. 8,667,490 B1 to van der Goot, entitled “Active/Active Storage and Virtual Machine Mobility Over Asynchronous Distances,” which is incorporated herein by reference.
While data and processes are moved between different sites, it is desirable that the cached data be kept coherent with respect to modifications that may be made to the data at the different sites. An example of a system for providing distributed cache coherence is described in U.S. Pat. No. 7,975,018 to Unrau et al., entitled “Systems and Methods for Providing Distributed Cache Coherency,” which is incorporated herein by reference. Other systems and techniques for managing and sharing storage array functions among multiple storage groups in a storage network are described, for example, in U.S. Pat. No. 7,266,706 to Brown et al. entitled “Methods and Systems for Implementing Shared Disk Array Management Functions,” which is incorporated herein by reference.
One drawback to maintain cache coherency is that, after a VM, application and/or process (hereinafter, collectively, “process”) is moved from an originating location to a destination location, the cached data for the process may be maintained on the originating location. Although cache coherency may provide cached data consistency, data access efficiency may suffer if a process on a first site needs to access cached data on a second site. Accordingly, it would be desirable to provide a system that addresses the above-noted problems and efficiently and effectively provides for handling cached data for a process that is moved from one site to another.